25 research outputs found

    Mapping inequalities in exclusive breastfeeding in low- and middle-income countries, 2000–2018

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    Exclusive breastfeeding (EBF)—giving infants only breast-milk for the first 6 months of life—is a component of optimal breastfeeding practices effective in preventing child morbidity and mortality. EBF practices are known to vary by population and comparable subnational estimates of prevalence and progress across low- and middle-income countries (LMICs) are required for planning policy and interventions. Here we present a geospatial analysis of EBF prevalence estimates from 2000 to 2018 across 94 LMICs mapped to policy-relevant administrative units (for example, districts), quantify subnational inequalities and their changes over time, and estimate probabilities of meeting the World Health Organization’s Global Nutrition Target (WHO GNT) of ≥70% EBF prevalence by 2030. While six LMICs are projected to meet the WHO GNT of ≥70% EBF prevalence at a national scale, only three are predicted to meet the target in all their district-level units by 2030

    Estimating cell type proportions in human cord blood samples from DNAm arrays

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    Epigenome-wide association studies are used to link patterns in the epigenome to human phenotypes and disease. These studies continue to increase in num- ber, driven by improving technologies and decreasing costs. However, results from population-scale association studies are often difficult to interpret. One major chal- lenge to interpretation is separating biologically relevant epigenetic changes from changes to the underlying cell type composition. This thesis focuses on computa- tional methods for correcting cell type composition in epigenome-wide association studies measuring DNAm in blood. Specifically, we focus on a class of methods, called reference-based methods, that rely on measurements of DNAm from puri- fied constituent cell types. Currently, reference-based correction methods perform poorly on human cord blood. This is unusual because adult blood, a closely related tissue, is a case-study in successful computational correction. Several previous attempts at improving cord blood estimation were only partially successful. We demonstrate how reference-based estimation methods that rely on for cord blood can be improved. First, we validated that existing methods perform poorly on cord blood, especially in minor cell types. Then, we demonstrated how this low per- formance stems from missing cell type references, data normalization and violated assumptions in signature construction. Resolving these issues improved estimates in a validation set with experimentally generated ground truth. Finally, we com- pared our reference-based estimates against reference-free techniques, an alterna- tive class of computational correction methods. Going forward, this thesis provides a template for extending reference-based estimation to other heterogeneous tissues.Science, Faculty ofComputer Science, Department ofGraduat

    Male circumcision and human papillomavirus infection in men: a systematic review and meta-analysis.

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    BACKGROUND: We systematically reviewed the evidence for an association between male circumcision and Human Papillomavirus (HPV) infection and genital warts in men. METHODS: PubMed and Embase were searched to 15 September 2010. The measure of effect was the adjusted odds ratio (OR) or rate ratio (RR) when present and the crude estimate otherwise. Random effects meta-analyses were used to calculate summary measures of effect. RESULTS: We identified 23 papers about the association between circumcision and HPV DNA. Circumcised men were less likely to have prevalent genital HPV infection than uncircumcised men (summary OR, 0.57, 95% confidence interval [CI], 0.45-0.71) with between-study heterogeneity (P-heterogeneity = 0.006; I(2) = 50.5%; 19 studies). Similar summary associations were seen in clinical and methodological subgroups. The effect of circumcision was stronger at the glans/corona (OR, 0.47; 95% CI, 0.37-0.60) and urethra (OR, 0.35; 95% CI, 0.12-1.05) compared with sites more distal to the foreskin. There was weak evidence that circumcision was associated with decreased HPV incidence (summary RR, 0.75, 95% CI, 0.57-0.99; 3 studies) and increased HPV clearance (summary RR, 1.33; 95% CI, 0.89-1.98; 3 studies) but no evidence of an association with prevalent genital warts (OR, 0.93, 95% CI, 0.65-1.33; 15 studies). CONCLUSIONS: Several countries are expanding access to voluntary medical male circumcision to reduce HIV prevalence. This could provide additional benefit in reducing HPV prevalence

    Social and structural factors associated with substance use within the support network of adults living in precarious housing in a socially marginalized neighborhood of Vancouver, Canada.

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    BACKGROUND:The structure of a social network as well as peer behaviours are thought to affect personal substance use. Where substance use may create health risks, understanding the contribution of social networks to substance use may be valuable for the design and implementation of harm reduction or other interventions. We examined the social support network of people living in precarious housing in a socially marginalized neighborhood of Vancouver, and analysed associations between social network structure, personal substance use, and supporters' substance use. METHODS:An ongoing, longitudinal study recruited 246 participants from four single room occupancy hotels, with 201 providing social network information aligned with a 6-month observation period. Use of tobacco, alcohol, cannabis, cocaine (crack and powder), methamphetamine, and heroin was recorded at monthly visits. Ego- and graph-level measures were calculated; the dispersion and prevalence of substances in the network was described. Logistic mixed effects models were used to estimate the association between ego substance use and peer substance use. Permutation analysis was done to test for randomness of substance use dispersion on the social network. RESULTS:The network topology corresponded to residence (Hotel) with two clusters differing in demographic characteristics (Cluster 1 -Hotel A: 94% of members, Cluster 2 -Hotel B: 95% of members). Dispersion of substance use across the network demonstrated differences according to network topology and specific substance. Methamphetamine use (overall 12%) was almost entirely limited to Cluster 1, and absent from Cluster 2. Different patterns were observed for other substances. Overall, ego substance use did not differ over the six-month period of observation. Ego heroin, cannabis, or crack cocaine use was associated with alter use of the same substances. Ego methamphetamine, powder cocaine, or alcohol use was not associated with alter use, with the exception for methamphetamine in a densely using part of the network. For alters using multiple substances, cannabis use was associated with lower ego heroin use, and lower ego crack cocaine use. Permutation analysis also provided evidence that dispersion of substance use, and the association between ego and alter use was not random for all substances. CONCLUSIONS:In a socially marginalized neighborhood, social network topology was strongly influenced by residence, and in turn was associated with type(s) of substance use. Associations between personal use and supporter's use of a substance differed across substances. These complex associations may merit consideration in the design of interventions to reduce risk and harms associated with substance use in people living in precarious housing

    Social and structural factors associated with substance use within the support network of adults living in precarious housing in a socially marginalized neighborhood of Vancouver, Canada.

    Get PDF
    BACKGROUND: The structure of a social network as well as peer behaviours are thought to affect personal substance use. Where substance use may create health risks, understanding the contribution of social networks to substance use may be valuable for the design and implementation of harm reduction or other interventions. We examined the social support network of people living in precarious housing in a socially marginalized neighborhood of Vancouver, and analysed associations between social network structure, personal substance use, and supporters' substance use. METHODS: An ongoing, longitudinal study recruited 246 participants from four single room occupancy hotels, with 201 providing social network information aligned with a 6-month observation period. Use of tobacco, alcohol, cannabis, cocaine (crack and powder), methamphetamine, and heroin was recorded at monthly visits. Ego- and graph-level measures were calculated; the dispersion and prevalence of substances in the network was described. Logistic mixed effects models were used to estimate the association between ego substance use and peer substance use. Permutation analysis was done to test for randomness of substance use dispersion on the social network. RESULTS: The network topology corresponded to residence (Hotel) with two clusters differing in demographic characteristics (Cluster 1 -Hotel A: 94% of members, Cluster 2 -Hotel B: 95% of members). Dispersion of substance use across the network demonstrated differences according to network topology and specific substance. Methamphetamine use (overall 12%) was almost entirely limited to Cluster 1, and absent from Cluster 2. Different patterns were observed for other substances. Overall, ego substance use did not differ over the six-month period of observation. Ego heroin, cannabis, or crack cocaine use was associated with alter use of the same substances. Ego methamphetamine, powder cocaine, or alcohol use was not associated with alter use, with the exception for methamphetamine in a densely using part of the network. For alters using multiple substances, cannabis use was associated with lower ego heroin use, and lower ego crack cocaine use. Permutation analysis also provided evidence that dispersion of substance use, and the association between ego and alter use was not random for all substances. CONCLUSIONS: In a socially marginalized neighborhood, social network topology was strongly influenced by residence, and in turn was associated with type(s) of substance use. Associations between personal use and supporter's use of a substance differed across substances. These complex associations may merit consideration in the design of interventions to reduce risk and harms associated with substance use in people living in precarious housing
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